A vibrating-sample magnetometer (VSM) is an accurate scientific instrument used to measure magnetic properties.

A magnetic material sample is first magnetized via a uniform external magnetic field. The sample is then sinusoidally vibrated via linear actuator or a mechanical vibrator. The induced voltage from the magnetized sample is sensed in a close-proximity pickup coil whereby the induced voltage is proportional to the sample’s magnetic moment, which in turn,  is directly dependent on the strength of the applied magnetic field. Typically, the induced voltage is measured via a lock-in amplifier where the output is used to generate the hysteresis curve of a material during the sweep of the applied external magnetic field.